Abstract: In this paper，the mass transfer efficiency of a new type structured packing of rhombus mesh frame used in extraction process was studied. In F50mm packed extraction columns，two extraction systems with different interfacial tensions，kerosene- benzoic acid-water and 30%TBP(kerosene)-acetic acid-water were chosen to examine the Hoxp (height of mass transfer unit based on plug flow and continuous flow) of this structured packing and F10mm Pall ring packing under various operation conditions. Eliminating the affecting factors，the Hoxp of this new type structured packing was less than that of Pall ring at a minimum rate of 25%，though the mass loading density of the rhombus mesh frame packing was only 38% of the Pall ring. Factors affecting mass transfer were discussed. Based on the characteristics of this packing，optimization and design principles were also suggested.